fix: improve AirbyteDateTime.__add__ to convert to standard datetime first

Co-Authored-By: Aaron <AJ> Steers <[email protected]>

Author: devin-ai-integration[bot]

airbyte_cdk/utils/datetime_helpers.py

@@ -220,9 +220,9 @@ def __add__(self, other: timedelta) -> "AirbyteDateTime":
             TypeError: If other is not a timedelta.
         """
         if isinstance(other, timedelta):
-            result = super().__add__(other)
-            if isinstance(result, datetime):
-                return AirbyteDateTime.from_datetime(result)
+            dt = self.to_datetime()
+            result = dt + other
+            return AirbyteDateTime.from_datetime(result)
         raise TypeError("Invalid operation")
 
     def __radd__(self, other: timedelta) -> "AirbyteDateTime":